This invention relates to a condenser-containing, ceramic multi-layer circuit board and a semiconductor module and a computer having the said circuit board.
With recent demands for faster electronic computers, the number of logical circuits susceptible to the simultaneous switching is increasing and generation of noises due to the simultaneous switching has been so far problems. In order to reduce the noises due to the simultaneous switching, it has been proposed to insert condensers into the circuits. [Japanese Patent Application Kokai (Laid-open) No. 57-56217]. By the insertion of the condensers, the noise voltage can be reduced and if the permissible noise level can be further made equal to the conventional noise level, the rise time of signal wave form, etc. can be shortened, so that a computing speed can be made about 1.5 times as high. Furthermore, the signal wave form can be effectively improved by the insertion of the condensers.
In order to fully obtain the effect of the condenser, the condenser must be provided as near a semiconductor chip as possible. In order to provide the condenser at a higher density, the condenser must be provided in a ceramic multi-layer circuit board.
Heretofore, a multi-layer circuit board having a condenser has been disclosed, for example, in Japanese Patent Applications Kokai (Laid-open) No. 57-37818 and 62-244631. That is, Japanese Patent Application Kokai (Laid-open) No. 57-37818 proposes to provide a number of small independent condenser elements in parallel connection in the individual layers in order to reduce the thermal stress due to a difference in the thermal expansion between the condenser dielectric material and the insulating material.
Japanese Patent Application Kokai (Laid-open) No. 62244631 proposes to provide a number of condensers in the individual layers in such a structure that the condenser dielectric material is in contact with the througholes through which electrical signals are transmitted. When the condenser dielectric material is provided in contact with the throughholes, as disclosed in Japanese Patent Application Kokai (Laid-open) No. 62-244631, a large time delay takes place in the transmission of electrical signals through the resions of high dielectric constant, and the higher speed effect ascribed to the provision of the condensers cannot be fully attained.